looking at that photo(original set up). there's a coupler on the intake..which is a NO..NO
in my book. You're taking a chance on air entering the fuel system more
than you have to. Plus i don't see any type of foam wrap around the fuel tank.

As someone mentioned, inspect the clunk line for small cuts

I uaually wrap soft foam around my fuel tank to prevent foaming due to
vibriations. Air bubbles in the fuel line will make the engine run lean at the
very least. You know.... what happens when you run too lean.lol

when the model in the air it's always going to run leaner. So tune it rich on the ground.
or hold the nose of the model up and tune it.

You should be able to see a smoke trail

The engine will dy due to over heating after a while, running too lean. if you're lucky
you're not going through glow plugs.

plus give your engine for time to break in
plus you have to tune pipe on it, so you'll have to richen it too.

Not sure how you use your throttle. Sometimes you need to clear out the pipe.

Another way to get more fuel in the intake line is to use a fuel filter..it's acts like a mini
hoper tank or install a slightly longer intake line.